The Acceptability of an Electronically Delivered Acceptance- and Mindfulness-Based Physical Activity Intervention for Survivors of Breast Cancer: One-Group Pretest-Posttest Design

Background: Survivors of breast cancer can face internal barriers to physical activity, such as uncertainty and frustration stemming from physical limitations, decreased physical functioning, fatigue, and pain. Interventions that draw from the principles of Acceptance and Commitment Therapy (ACT) may help survivors of breast cancer overcome some of the internal barriers associated with physical activity. Objective: The primary aim of this study was to investigate the acceptability of an electronically delivered physical activity intervention for survivors of breast cancer, centered on ACT processes. Methods: This study used a 1-group pretest-posttest design. We recruited 80 insufficiently active female survivors of breast cancer using a web-based recruitment strategy. The 8-week intervention consisted of weekly modules that featured didactic lessons and experiential exercises targeting key ACT processes in the context of physical activity promotion (namely, values, committed action, acceptance, defusion, and contacting the present moment). We determined intervention acceptability according to study retention (≥70%), adherence rates (≥75% of the participants completing ≥50% of the modules), and posttest survey scores reflecting the perceived ease of use, perceived usefulness, and interest and enjoyment of the intervention (≥5 on a 7-point Likert-type scale). We also evaluated changes in self-reported aerobic and muscle strengthening-physical activity, physical activity acceptance, physical activity regulation, and health-related outcomes. Results: The retention rate (61/80, 76%), adherence rate (60/80, 75%), average perceived ease of use (6.17, SD 1.17), perceived usefulness (5.59, SD 1.40), and interest and enjoyment scores (5.43, SD 1.40) met the acceptability criteria. Participants increased their self-reported aerobic physical activity (Cohen d=1.04), muscle strengthening-physical activity (Cohen d=1.02), physical activity acceptance (cognitive acceptance: Cohen d=0.35; behavioral commitment: Cohen d=0.51), physical activity regulation (identified regulation: Cohen d=0.37; integrated regulation: Cohen d=0.66), increased their ability to participate in social roles and activities (Cohen d=0.18), and reported less fatigue (Cohen d=0.33) and sleep disturbance (Cohen d=0.53). Conclusions: Electronically delivered acceptance- and mindfulness-based interventions may be useful for promoting physical activity in survivors of breast cancer. Further research is needed to refine these approaches and evaluate their effectiveness.